Steel strapping is the strongest of all the strapping materials. It is recommended where high strength is necessary, low elongation (stretch) is important, and where the product may be sharp or hot. Steel strapping is sealed using mechanical seals and notch (sealless) type joints. While it is still the preferred alternative in many industries, the market for steel is declining, largely because it can be dangerous to work with (presenting sharp edges) and is difficult to recycle.
Advantages - High strength, low elongation
Disadvantages - Relatively expensive, sharp edges, difficult to recycle
Applications - Sharp or hot products, steel, rail car, heavy construction
Polypropylene Strapping
Polypropylene strapping is the most commonly used and least expensive of all strapping materials. It is light, easy to apply, and easy to recycle. It's primary characteristics are high elongation (stretch) and elongation recovery. It has, however, a low retained tension. Polypropylene strapping is available in hand grade and machine grade, and can be sealed with buckles, seals, heat seals, or friction welds. Worth noting, machine grade strapping can be used with manual tools, but hand grade strapping should not be used in a machine application. Polypropylene is used in all automatic strapping machines and almost all stand-alone arch strapping machines.
Advantages - Most cost effective, lightweight, easy to apply, easy to recycle, high elongation, high elongation recover
Disadvantages - Low retained tension, potential to split
Applications - Light duty palletizing, unitizing, carton closing, bundling
Polyester Strapping
Polyester (or PET) is the most rigid of the strapping options. It has significantly less elongation than polypropylene and retains tension over a longer period of time. Polyester strap is nick resistant and is sealed with seals, heat, or friction welds.
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| Polypropylene (L), Polyester (R) |
Advantages - Most rigid, long tension retention, high strength, nick resistant, easy to recycle
Disadvantages - Less elongation than polypropylene
Applications - Empty cans and bottles, lumber, heavy/rigid pallet loads, steel replacement
Discerning Polypropylene from Polyester Strapping
Plastic strapping, in general, is often referred to collectively as "poly strapping." This can create much confusion when attempting to order or obtain quotes since poly strapping could be either polypropylene or polyester. Polypropylene strap is typically embossed (per the graphic above) and feels more like plastic. It is usually a more of a matte finish. Polyester is a glossy, smooth strap. Polyester strap does not resemble polyester fabric in any way. Since polypropylene is the most common plastic strap option, "poly strapping" will generally refer to polypropylene. Still, it is important to be able to differentiate between the two in order to be certain you or your customer procure the correct material.
Cord Strapping
Advantages - Can be manual applied with no tools, moisture resistant
Disadvantages - Poor elongation, difficult to recycle
Applications - Steel replacement, agricultural, boating
The chart below illustrates the advantages of each type of strapping and compares the relative performance of each. It also indicates what types of applications will work with that material. Definitions of these characteristics can be found below.
Strapping Tools and Options
Be careful when selecting any strapping tools. Some tools can be used on any plastic strap, some can only be used on polyester or polypropylene, and some can only be used on one type of strap. Most are also limited to a certain size range (width and/or thickness). There are no tools that cover every strap size and/or type. Tools for steel strapping are always exclusive to steel strap only.
No tools are required, only buckles that the strap is wound through. The strap is hand-tightened.
Advantages - No tools required, most convenient
Disadvantages - Maximum working range of the strap is not achievable
Strap Type - Cord only
Requires a tensioner, a sealer, and seals. This is the most common way of applying strapping.
Advantages - Allows the achievement of the maximum, or near maximum, working range of the strap; secure
Disadvantages - Requires multiple tools and the appropriate seals
Strap Types - All: Polypropylene, polyester, cord, steel
Battery Operated Tools
Combines all the necessary operations in one tool - tensioning, sealing, and cutting. Offered in varying strengths to accommodate the unique needs of the user.Advantages - Consolidates all strapping functions in to one tool, portable, efficient, requires no seals, enables achievement of a specific amount of tension
Disadvantages - Can be lost or damaged due to their portability, least durable of the powered tools
Strap Types - Polypropylene, polyester
Pneumatic Tools
Advantages - Consolidates all strapping functions in to one tool, efficient, powerful, requires no seals, enables the achievement of a specific amount of tension
Disadvantages - not portable (requires a compressed air source), heavier than battery tools
Strap Types - Polypropylene, polyester, steel
Machines
Advantages - Consolidates all strapping functions, fast, efficient, automatic or semi-automatic, requires no seals, can integrate with an assembly line or conveyor system, allows achievement of a specific amount of tension
Disadvantages - The most expensive strapping option, relatively large footprint, require and power and/or pressurized air source, limited as to the size/weight of the box that they can strap
Strap Types - Polypropylene (smaller machines), polypropylene or polyester (larger machines)
Strapping Characteristics and Definitions
General Terms:
Elongation - The amount of stretch in the strap as tension is applied
Elongation Recovery - The strap's ability to return to its original state after tensioning
Hand Grade Strapping - Designed to be applied by hand with manual, electric or pneumatic tools. Cannot be used in a semi-automatic or automatic strapping machine.
The following terms are necessary to understand when purchasing/selecting strapping:
Break Strength - The amount of force, in pounds, required to break the strap
Core Size - the diameter and depth of one coil of the strap. This must correspond to the dispenser or machine being used with the strapping.
Thickness - this is the physical thickness of the strap, measured in fractions of an inch, such as .020"
Width - the physical width of the strap, it must correspond with the tools or machine being used to apply the strap
Color - the color of the strap is completely subjective and has no impact on the performance of the strap
Embossing - the diamond-shaped textured pattern applied to most polypropylene strapping. It enhances split resistance, improves stiffness characteristics, and increases joint efficiency.
AAR Approved - AAR is the American Association of Railroads and AAR approved strapping is strapping that has been approved by AAR and bears their seal for safely transporting bundled material on rail cars
Contact us with any additional questions you may have and we will be happy to assist you in determining the type of strap needed for your unique application.
